Beverage forming systems that use a liquid, such as water, to form a beverage are well known. For example, U.S. Patent Application Publication 2011/0185907 discloses a coffee machine and receptacle that can be docked at a filling position on the machine to receive coffee made by the machine. The machine can detect the presence of the receptacle at the filling position, and starts an operating mode to produce coffee when the receptacle is at the filling position.